PlanetScale

PlanetScale is a serverless database platform compatible with MySQL. It is built on Vitess, the technology used by YouTube/Slack to scale massively.

When to Use

• High Traffic MySQL: When you need "sharding" but don't want to build it yourself.
• Schema Management: excellent "Branching" workflow (Development -> Staging -> Production) without downtime (Online DDL).
• Connections: Handles 100,000s of concurrent connections (Vitess architecture).

Quick Start

Uses standard MySQL drivers.

# Connect via CLI
pscale shell my-database main

Core Concepts

Branching

Treat your database schema like Git code.

1. Create a dev branch from main.
2. Apply migrations to dev.
3. Open a "Deploy Request" to merge dev to main.
4. PlanetScale runs the schema change online without locking tables.

Vitess

Abstracts the sharding. Your app sees one big DB, but behind scenes it might be 100 shards.

Non-Blocking Schema Changes

Ghost/PT-OSC style schema changes standard. You never lock the table for "ALTER TABLE".

Best Practices (2025)

Do:

• Use Foreign Keys carefully: PlanetScale supports them now (mostly), but conceptually in sharded systems, application-level joins are often safer/faster.
• Use pscale CLI: Great developer experience for managing branches.
• Safe Migrations: Use the Branching workflow. Never run ALTER TABLE directly on production main branch.

Don't:

• Don't use stored procedures/triggers: Vitess generally discourages logic in the DB. Move logic to app.

References

• PlanetScale Documentation